As an avid scuba diver, I am well-acquainted with the fact that there is plenty of sunlight underwater to see things even on cloudy days. So, I wasn't surprised to read that scientists from the U.S. Naval Research Laboratory, Electronics Science and Technology Division, are researching underwater photovoltaic technology that could help provide an energy source for various electronic sensor systems at depths of up to 30 feet.
Although research to date has been limited, there is early evidence showing that the spectral content of solar radiation underwater might lend itself to high-conversion efficiency -- if the solar cell material is matched to the unique wavelength.
The Navy is studying high-quality gallium indium phosphide cells for underwater applications. These cells are well suited to operating at high efficiency in low lighting conditions, according to information on the Naval Research Laboratory's Web site.
In a statement, researcher Phillip Jenkins notes:
"The use of autonomous systems to provide situation awareness and long-term environment monitoring underwater is increasing. Although water absorbs sunlight, the technical challenge is to develop a solar cell that can efficiently convert these underwater photons to electricity."
So far, research have been able to produce 7 watts per 10 square feet (approximately) of solar cells, according to the initial Navy information disclosing the research.